1. Field of the Invention
The present invention relates to a transportation apparatus and, more particularly, an apparatus for transporting cargo such as rolls of aluminum stock.
2. Description of the Background
Aluminum cans and numerous other products are made from aluminum sheet stock which the aluminum producer provides in rolls resembling rolls of toilet tissue. However, the rolls of aluminum stock are generally approximately sixty inches high, have diameters up to six feet and greater and weigh from 10 to 20 thousand pounds.
In order to transport the rolls of aluminum stock from the aluminum producer to the end user e.g. the aluminum can maker, it is common to transport the rolls by tractor-trailer rigs, so called eighteen-wheelers. Not infrequently, the aluminum producer and the end user are in distinctly different climatic zones. Thus, the aluminum stock may be produced in a climatic zone which is quite cold whereas the end user may be located in a climatic zone which is relatively warm. Thus, it is common for these rolls of aluminum stock to be transported from climatic zones where the temperature is 20.degree. F. to a climatic zone where the temperature is 80.degree. F. It is known that when the rolls of aluminum stock undergo these rather drastic temperature changes during transport, the aluminum is prone to water spotting resulting in discoloration of the stock making it unsuitable for many end uses. Although the phenomena is not totally understood, it is believed that in being transported from a cold climatic zone to a warm climatic zone, the aluminum stock sweats leading to the water spotting and discoloration. This can be quite expensive for the aluminum producer as customarily the producer bears the loss if the aluminum stock arrives at the end user's location in a water spotted condition.
Typically, when the rolls of aluminum stock are transported by tractor-trailer rigs, it is done on a flat bed trailer, the rolls of aluminum stock disposed on pallets, being positioned on the trailer floor at suitable locations and then covered with a tarp so as to insulate the rolls of aluminum stock, to the degree possible, from temperature changes and hence prevent water spotting. It will be readily recognized that the use of tarps to insulate against temperature changes is far from satisfactory particularly when the temperature changes may be quite severe.
While the use of a trailer in the form of an enclosed van in which the temperature could be controlled to prevent the water spotting would be desirable, heretofore it has not been possible to use enclosed vans or trailers for the transport of large rolls of metal stock. As was noted above, the rolls of metal stock can weigh anywhere from 10 to 20 thousand pounds each. For purposes of economy in transporting rolls of metal stock by a tractor-trailer rig, it is generally desirable that the load range from about 40 to about 45 thousand pounds. Typically, in terms of rolls of metal stock this would involve generally three rolls of stock the combined weight of which was in the desired range. In order to ensure stability and handling of the rig during transport, the three rolls are usually positioned such that one roll sits over the front axle of the trailer, a second roll is disposed generally in the middle of the trailer and the third roll is disposed over the rear axle of the trailer.
Because of this weight, in order to load the rolls of metal stock into a van-type trailers, it would be necessary to use a forklift. Thus, a forklift carrying the pallet with the roll of metal stock would enter from the rear end of the van, deposit the roll in the forward end of the van over the front axle, back out of the van and repeat the process with the second and third rolls. However, this is not practical because of the fact that in order to lift a 15 to 20 thousand pound roll of metal stock, it is necessary to employ a forklift which itself weighs approximately 35 thousand pounds. This means that in loading a 20 thousand pound roll of metal stock into a van to be positioned over the front axle, the van would have to bear a total load of 50 thousand pounds. This exceeds the load capacity that a typical van can support between the front and rear axles of the van. While theoretically the undercarriage of the van could be reinforced to support this weight, practically, that cannot be done because of the fact that the added structural support increases the weight of the van to the point where the desired load of 40 to 45 thousand pounds cannot be carried. In this regard it is to be observed that federal law generally prohibits loads of greater than 80 thousand pounds on interstate highways. Thus, although the van could be structurally reinforced to bear the combined weight of the forklift and a 20 thousand pound roll of metal stock, this would mean that the load that could be carried would be less than the 40 to 45 thousand pounds thereby greatly increasing the cost of transportation of the rolls.